A corrections officer in Nebraska was killed after being attacked by a teenage inmate on Friday.

Dylan Cardeilhac, 15, of Torrington, Wyo., is accused of strangling Amanda Baker, 24, early Friday morning. The teenager was being held in the Scotts Bluff County Detention Center on charges of armed robbery and use of a weapon to commit a felony in connection with the robbery of a gas station, Omaha.com reported.

Baker was declared brain dead Friday afternoon, according to the report, and was kept alive on life support long enough for her organs to be harvested.

An autopsy was to be conducted today.

Cardeilhac is now expected to be charged with first-degree murder. He is now isolated in the jail.

Authorities don’t know why Baker was in Cardeilhac’s cell when the inmate apparently grabbed the officer from behind and strangled her with his arm, Omaha.com reported. It was against jail policy for her to enter his cell alone.

Baker had worked at Scotts Bluff County Detention Center since June 2012, in both the adult and juvenile corrections facilities